/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.core.style;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;

/**
 * Spring's default {@code toString()} styler.
 *
 * <p>This class is used by {@link ToStringCreator} to style {@code toString()}
 * output in a consistent manner according to Spring conventions.
 *
 * @author Keith Donald
 * @author Juergen Hoeller
 * @since 1.2.2
 */
public class DefaultToStringStyler implements ToStringStyler
{

    private final ValueStyler valueStyler;


    /**
     * Create a new DefaultToStringStyler.
     *
     * @param valueStyler the ValueStyler to use
     */
    public DefaultToStringStyler(ValueStyler valueStyler)
    {
        Assert.notNull(valueStyler, "ValueStyler must not be null");
        this.valueStyler = valueStyler;
    }

    /**
     * Return the ValueStyler used by this ToStringStyler.
     */
    protected final ValueStyler getValueStyler()
    {
        return this.valueStyler;
    }


    @Override
    public void styleStart(StringBuilder buffer, Object obj)
    {
        if (!obj.getClass().isArray())
        {
            buffer.append('[').append(ClassUtils.getShortName(obj.getClass()));
            styleIdentityHashCode(buffer, obj);
        }
        else
        {
            buffer.append('[');
            styleIdentityHashCode(buffer, obj);
            buffer.append(' ');
            styleValue(buffer, obj);
        }
    }

    private void styleIdentityHashCode(StringBuilder buffer, Object obj)
    {
        buffer.append('@');
        buffer.append(ObjectUtils.getIdentityHexString(obj));
    }

    @Override
    public void styleEnd(StringBuilder buffer, Object o)
    {
        buffer.append(']');
    }

    @Override
    public void styleField(StringBuilder buffer, String fieldName, @Nullable Object value)
    {
        styleFieldStart(buffer, fieldName);
        styleValue(buffer, value);
        styleFieldEnd(buffer, fieldName);
    }

    protected void styleFieldStart(StringBuilder buffer, String fieldName)
    {
        buffer.append(' ').append(fieldName).append(" = ");
    }

    protected void styleFieldEnd(StringBuilder buffer, String fieldName)
    {
    }

    @Override
    public void styleValue(StringBuilder buffer, @Nullable Object value)
    {
        buffer.append(this.valueStyler.style(value));
    }

    @Override
    public void styleFieldSeparator(StringBuilder buffer)
    {
        buffer.append(',');
    }

}
